US10316967B2 - Control device for continuously variable transmission - Google Patents

Control device for continuously variable transmission Download PDF

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US10316967B2
US10316967B2 US15/559,472 US201615559472A US10316967B2 US 10316967 B2 US10316967 B2 US 10316967B2 US 201615559472 A US201615559472 A US 201615559472A US 10316967 B2 US10316967 B2 US 10316967B2
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road
rotation speed
predetermined value
bad road
wheel
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US20180119813A1 (en
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Kosuke Abe
Shin TSUKAMOTO
Seiichiro Takahashi
Hiroyasu Tanaka
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Nissan Motor Co Ltd
JATCO Ltd
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Nissan Motor Co Ltd
JATCO Ltd
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Assigned to NISSAN MOTOR CO., LTD., JATCO LTD reassignment NISSAN MOTOR CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TSUKAMOTO, SHIN, ABE, KOSUKE, TAKAHASHI, SEIICHIRO, TANAKA, HIROYASU
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/66—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings
    • F16H61/662—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/66—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings
    • F16H61/662—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members
    • F16H61/66272—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members characterised by means for controlling the torque transmitting capability of the gearing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H59/00—Control inputs to control units of change-speed- or reversing-gearings for conveying rotary motion
    • F16H59/36—Inputs being a function of speed
    • F16H59/38—Inputs being a function of speed of gearing elements
    • F16H59/40—Output shaft speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/0021—Generation or control of line pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/02—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing characterised by the signals used
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H9/00—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members
    • F16H9/02—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion
    • F16H9/04—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes
    • F16H9/12—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members
    • F16H9/16—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members using two pulleys, both built-up out of adjustable conical parts
    • F16H9/18—Gearings for conveying rotary motion with variable gear ratio, or for reversing rotary motion, by endless flexible members without members having orbital motion using belts, V-belts, or ropes engaging a pulley built-up out of relatively axially-adjustable parts in which the belt engages the opposite flanges of the pulley directly without interposed belt-supporting members using two pulleys, both built-up out of adjustable conical parts only one flange of each pulley being adjustable
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W2520/00—Input parameters relating to overall vehicle dynamics
    • B60W2520/28—Wheel speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H59/00—Control inputs to control units of change-speed- or reversing-gearings for conveying rotary motion
    • F16H59/36—Inputs being a function of speed
    • F16H59/46—Inputs being a function of speed dependent on a comparison between speeds
    • F16H2059/465—Detecting slip, e.g. clutch slip ratio
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H59/00—Control inputs to control units of change-speed- or reversing-gearings for conveying rotary motion
    • F16H59/50—Inputs being a function of the status of the machine, e.g. position of doors or safety belts
    • F16H2059/506—Wheel slip
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
    • F16H61/66—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings
    • F16H61/662—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members
    • F16H61/66272—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members characterised by means for controlling the torque transmitting capability of the gearing
    • F16H2061/66277—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings with endless flexible members characterised by means for controlling the torque transmitting capability of the gearing by optimising the clamping force exerted on the endless flexible member
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H59/00—Control inputs to control units of change-speed- or reversing-gearings for conveying rotary motion
    • F16H59/36—Inputs being a function of speed
    • F16H59/38—Inputs being a function of speed of gearing elements
    • F16H59/42—Input shaft speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H59/00—Control inputs to control units of change-speed- or reversing-gearings for conveying rotary motion
    • F16H59/36—Inputs being a function of speed
    • F16H59/46—Inputs being a function of speed dependent on a comparison between speeds
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16H—GEARING
    • F16H59/00—Control inputs to control units of change-speed- or reversing-gearings for conveying rotary motion
    • F16H59/60—Inputs being a function of ambient conditions
    • F16H59/66—Road conditions, e.g. slope, slippery
    • Y10T477/624—

Definitions

  • the present invention relates to a control device for a continuously variable transmission.
  • Patent Document 1 As a technique that accurately judges a road surface condition and controls a pressure of a compression force (a belt clamping force) of a belt type continuously variable transmission properly according to an actual road surface condition, it has been disclosed in Patent Document 1. More specifically, a detection value of a rotation speed (the number of revolutions) of a driving wheel is subjected to a band-pass filter process, and a value obtained by this band-pass filter process is subjected to time total integration, then the road surface condition is judged according to this time total integration value. In a case where the road surface condition is judged to be a no-good road, the compression force is set to be higher than that of a case where the road surface condition is judged to be a good road.
  • Patent Document 1 Japanese Unexamined Patent Application Publication No. JP2003-269591
  • An object of the present invention is therefore to provide a control device for the continuously variable transmission which is capable of suppressing the belt slip regardless of the road condition.
  • a control device for a continuously variable transmission comprises: a first rotation speed sensor detecting a rotation speed of a driving wheel; a second rotation speed sensor detecting a rotation speed of a driven wheel; a wheel speed difference detection unit configured to detect a wheel speed difference between the driving wheel and the driven wheel from a detection value of the first rotation speed sensor and a detection value of the second rotation speed sensor; a bad road judgment unit configured to, when the wheel speed difference is equal to or greater than a first predetermined value, judge that a road on which a vehicle is travelling is a bad road; a first belt clamping force increase unit configured to, in a case where the road is judged to be the bad road, increase a belt clamping force when clamping a belt of the continuously variable transmission by pressure-controlled pulleys as compared with a case where the road is not judged to be the bad road; a vibration detection unit configured to detect a vehicle speed vibration value indicating a vibration of a vehicle speed on the basis of at least one of the detection
  • the compression force (the belt clamping force) can be immediately increased when the driving wheel slips. Therefore, the belt slip caused by increase of the grip force of the driving wheel after the slip can be avoided. Further, even before detecting the bad road, since a possibility of occurrence of the belt slip is strong when the wheel speed difference is equal to or greater than the second predetermined value or the vehicle speed vibration value is equal to or greater than the third predetermined value, or since a possibility that subsequently the bad road will be judged is strong, by increasing the compression force (the belt clamping force) in this case, the belt slip can be suppressed.
  • FIG. 1 is a system diagram showing a configuration of a control device for a continuously variable transmission according to an embodiment 1.
  • FIG. 2 is a flow chart showing a bad road (rough road) control process according to the embodiment 1.
  • FIG. 3 is a flow chart showing a bad road (rough road) control process according to the embodiment 1.
  • FIG. 4 is a control block diagram for executing a vehicle speed vibration component extraction process according to the embodiment 1.
  • FIG. 5 is a time chart showing the bad road (rough road) control process according to the embodiment 1.
  • a “good road” means a pavement paved with asphalt or concrete.
  • a “bad road (rough road)” means an unpaved road such as a gravel road and a cobblestone road.
  • the bad road includes, in particular, from among the bad road, a road where an obstruction such as a large stone, a lumber (wood) and a curb and/or a road surface subsidence spot are present in a travelling direction, a road surface is rough or bumpy and a sudden torque is inputted to the transmission from the driving wheel.
  • the “sudden torque” means a sudden large torque temporarily inputted to the transmission from the driving wheel, which occurs when an idling (or slipping) driving wheel contacts the road surface again when or after a vehicle overrides the obstruction.
  • FIG. 1 is a system diagram showing a configuration of a control device for a continuously variable transmission according to the embodiment 1.
  • a belt type continuously variable transmission (hereinafter, called “CVT”) 1 is provided so that a V-groove of a primary pulley 2 and a V-groove of a secondary pulley 3 are aligned with each other, and a belt 4 is wound around the V-grooves between these pulleys 2 and 3 .
  • An engine 5 that is a drive source is coaxially aligned with the primary pulley 2 .
  • a torque converter 6 having a lock-up clutch 6 c and a forward-reverse switching mechanism 7 are provided.
  • the forward-reverse switching mechanism 7 has, as a main element or component, a double pinion planetary gear set 7 a . And its sun gear is connected to the engine 5 through the torque converter 6 , and its carrier is connected to the primary pulley 2 .
  • the forward-reverse switching mechanism 7 further has a forward clutch 7 b that directly connects the sun gear and the carrier of the double pinion planetary gear set 7 a and a reverse brake 7 c that fixes a ring gear. When the forward clutch 7 b is engaged, an input rotation from the engine 5 is transmitted to the primary pulley 2 as it is through the torque converter 6 .
  • a mechanical oil pump O/P is provided at a pump impeller side of the torque converter 6 . This mechanical oil pump O/P is driven by the engine 5 , and supplies a hydraulic pressure to an after-mentioned shift control hydraulic control circuit 11 .
  • a rotation of the primary pulley 2 is transmitted to the secondary pulley 3 through the belt 4 , and a rotation of the secondary pulley 3 is transmitted to a driving wheel (not shown) through an output shaft 8 , a gear set 9 and a differential gear unit 10 .
  • a rotation of the secondary pulley 3 is transmitted to a driving wheel (not shown) through an output shaft 8 , a gear set 9 and a differential gear unit 10 .
  • one sides of conical plates forming the V-grooves of the primary pulley 2 and the secondary pulley 3 are stationary conical plates 2 a and 3 a
  • the other sides are movable conical plates 2 b and 3 b that can move in the respective axial directions.
  • the primary pulley pressure Ppri and the secondary pulley pressure Psec are controlled by the shift control hydraulic control circuit 11 .
  • the shift control hydraulic control circuit 11 performs the control in response to a signal from a transmission controller 12 .
  • the transmission controller 12 inputs a signal from a primary pulley rotation sensor 13 (corresponding to a third rotation speed sensor) that detects a rotation speed Npri of the primary pulley 2 , a signal from a secondary pulley rotation sensor 14 that detects a rotation speed Nsec of the secondary pulley 3 , a signal from a secondary pulley pressure sensor 15 that detects a secondary pulley pressure Psec, a signal from an accelerator operation amount sensor 16 that detects an operation amount APO of an accelerator pedal, a selection range signal from an inhibitor switch 17 that detects a position of a selection lever, a signal from an oil temperature sensor 18 that detects a working fluid temperature TMP of the CVT 1 , a signal (such as an engine rotation speed and a fuel injection time) relating to an input torque Tq from an engine controller 19 that controls the engine 5 , and a signal from a wheel speed sensor 21 (a wheel speed sensor 21 F for a front wheel of the driving wheel, and a wheel speed sensor 21 R for a rear wheel of
  • the transmission controller 12 calculates a wheel speed difference between the front and rear wheels from the wheel speed sensor 21 F for the front wheel of the driving wheel and the wheel speed sensor 21 R for the rear wheel of the driven wheel, and judges a bad road travelling (a rough road travelling) from a magnitude of the wheel speed difference. Then, when judged to be the bad road travelling, the transmission controller 12 executes a bad road-detected control process.
  • the bad road-detected control process is a process in which the lock-up clutch 6 c is released, torque capacities of the pulleys 2 and 3 are increased by outputting a command for increasing the secondary pulley pressure Psec (hereinafter, also called a compression force (or a belt clamping force)) to a bad road control pressure P 1 to the shift control hydraulic control circuit 11 , and a command (a fuel injection amount reduction command, an intake air amount reduction command etc.) for decreasing an output torque of the engine 5 is outputted to the engine controller 19 so that an input torque to the CVT 1 is smaller than the torque capacity of the pulley.
  • a command for increasing the secondary pulley pressure Psec hereinafter, also called a compression force (or a belt clamping force)
  • a command a fuel injection amount reduction command, an intake air amount reduction command etc.
  • the compression force (the belt clamping force) can be immediately increased when the driving wheel slips, and a belt slip caused by increase of a grip force of the driving wheel after the slip can be avoided. Therefore, such a belt compression force that the belt 4 does not slip even if the input of the sudden torque is present is provided to the secondary pulley 3 and its torque capacity is increased, while the input torque to the CVT 1 is decreased, thereby effectively protecting the CVT 1 from the sudden torque.
  • FIGS. 2 and 3 are flow charts showing the bad road (rough road) control process according to the embodiment 1.
  • step S 01 a judgment is made as to whether or not a vehicle speed vibration fvsp is equal to or greater than a vehicle speed vibration reference secondary pressure lower limit regulation value (hereinafter, called fvsp_psec, corresponding to a third predetermined value). If the condition is satisfied, the routine proceeds to step S 02 . If the condition is not satisfied, the routine proceeds to step S 03 .
  • fvsp_psec vehicle speed vibration reference secondary pressure lower limit regulation value
  • FIG. 4 is a control block diagram for executing a vehicle speed vibration component extraction process according to the embodiment 1.
  • a vehicle speed conversion unit 101 converts a wheel speed sensor pulse period (or a wheel speed sensor pulse cycle) inputted from the wheel speed sensor 21 R into the vehicle speed. Because an operation cycle of the controller is fixed, it is possible to convert the number of pulses inputted within the operation cycle into the vehicle speed.
  • a high-pass filter 102 extracts only a high-frequency side signal from the converted vehicle speed signals and outputs it. Regarding a change of the vehicle speed when travelling on the good road, it changes only at a low frequency by an influence of an inertia of the vehicle.
  • the signal at the high-frequency side is considered to be a vibration component.
  • a low-pass filter 103 smoothes the high-frequency side vehicle speed. Regarding the wheel, a frequency range in which the wheel can actually vibrate is limited due to an influence of an inertia of the wheel. Therefore, by removing noises by the low-pass filter 103 and extracting vibration that actually occurs at the wheel, the vehicle speed vibration fvsp that is the vibration component is extracted.
  • the secondary pulley pressure Psec is set to Psec(fvsp) that is a value according to the vehicle speed vibration fvsp. More specifically, the secondary pulley pressure Psec is set so that the greater the vehicle speed vibration fvsp is, the greater the secondary pulley pressure Psec is. This is because even in a state in which a wheel speed difference ⁇ vfr is not judged to be a no-good road at an after-mentioned step S 06 , there is apprehension that the belt slip will occur when the vehicle speed vibration fvsp actually becomes great.
  • the secondary pulley pressure Psec is set to a secondary pulley pressure Psec(n) that is calculated according to a normal control.
  • the secondary pulley pressure Psec is shifted to Psec(n) from a state in which the secondary pulley pressure Psec has been set to Psec(fvsp)
  • the secondary pulley pressure Psec is shifted to Psec(n) with a secondary pulley pressure change rate ⁇ Psec being limited to a predetermined change rate ⁇ Psec_lim.
  • step S 04 a judgment is made as to whether or not the wheel speed difference ⁇ vfr, which is a difference between a rotation speed of the driving wheel detected by the wheel speed sensor 21 F and a rotation speed of the driven wheel detected by the wheel speed sensor 21 R, is equal to or greater than a wheel speed difference reference secondary pressure lower limit regulation value (hereinafter, called ⁇ vfr_psec, corresponding to a second predetermined value) that is smaller than an after-mentioned entry judgment threshold value ⁇ vfr_br (corresponding to a first predetermined value) for a bad road detection.
  • ⁇ vfr_psec a wheel speed difference reference secondary pressure lower limit regulation value
  • the secondary pulley pressure Psec is set to a magnitude according to the wheel speed difference ⁇ vfr. More specifically, a function connecting a current secondary pulley pressure Psec (Psec(fvsp) or Psec(n)) for ⁇ vfr_psec and the bad road control pressure P 1 for ⁇ vfr_br is defined, and a ramp control is performed so that the greater the wheel speed difference ⁇ vfr is, the more the secondary pulley pressure Psec is increase toward the bad road control pressure P 1 .
  • a secondary pulley pressure determined by this ramp control is termed Psec(fvsp, ⁇ vfr).
  • step S 06 a judgment is made as to whether or not the wheel speed difference ⁇ vfr is equal to or greater than a wheel speed difference reference primary rotation speed lower limit regulation value (hereinafter, called ⁇ vfr_npri, corresponding to a fourth predetermined value), or a judgment is made as to whether or not the vehicle speed vibration fvsp is equal to or greater than a vehicle speed vibration reference primary rotation speed lower limit regulation value (hereinafter, called fvsp_npri, corresponding to a fifth predetermined value). If the condition is satisfied, the routine proceeds to step S 07 . If the condition is not satisfied, the routine proceeds to step S 08 .
  • a wheel speed difference reference primary rotation speed lower limit regulation value hereinafter, called ⁇ vfr_npri, corresponding to a fourth predetermined value
  • fvsp_npri vehicle speed vibration reference primary rotation speed lower limit regulation value
  • This primary pulley minimum rotation speed Npri_min is such a value that even if the bad road control pressure P 1 is required to use in the bad road control of the secondary pulley pressure Psec, a pump discharge pressure can surely be secured.
  • the lock-up clutch 6 c is released. In this case, in addition to the control of the transmission ratio G, by requiring the engine 5 to attain a rotation speed corresponding to the primary pulley minimum rotation speed Npri_min, the discharge pressure of the mechanical oil pump O/P is secured.
  • step S 08 the transmission ratio G of the CVT 1 is controlled according to a normal shift map.
  • the lock-up clutch 6 c of the torque converter 6 is in a lock-up state, and the rotation speed Npri of the primary pulley 2 of the CVT 1 and an engine rotation speed Ne are identical. Since the mechanical oil pump O/P is driven by the engine 5 , if the engine rotation speed Ne is decreased when increasing the secondary pulley pressure Psec according to fvsp or ⁇ vfr, there is a risk that an adequate oil pump discharge pressure will not be secured. Therefore, in order to secure the oil pump discharge pressure of the mechanical oil pump O/P, the primary pulley minimum rotation speed Npri_min is set, and the minimum rotation limit regulation process to control the transmission ratio G of the CVT 1 to achieve this rotation speed is performed. With this control, the primary rotation speed Npri is secured, which results in the engine rotation speed Ne being secured, then the oil pump discharge pressure of the mechanical oil pump O/P is secured, and the belt slip is prevented.
  • step S 09 a judgment is made as to whether or not the wheel speed difference ⁇ vfr is equal to or greater than the bad road detection entry judgment threshold value ⁇ vfr_br. If the condition is satisfied, the routine proceeds to step S 010 , and a bad road detection flag is set to ON. If the condition is not satisfied, the routine proceeds to step S 011 , and the bad road detection flag is set to OFF.
  • step S 1 a judgment is made as to whether or not the bad road detection flag is ON. If the bad road detection flag is ON, the routine proceeds to step S 2 . If the bad road detection flag is OFF, that is, if the road is the good road, the present control flow is ended.
  • step S 2 the bad road-detected control is executed. More specifically, the lock-up clutch 6 c is released, and the secondary pulley pressure Psec is increased to the bad road control pressure P 1 .
  • step S 3 a judgment is made as to whether or not the wheel speed difference ⁇ vfr is equal to or less than a cancellation judgment threshold value (corresponding to sixth and eighth predetermined values). If the wheel speed difference ⁇ vfr is equal to or less than the cancellation judgment threshold value, the routine proceeds to step S 5 . If the wheel speed difference ⁇ vfr is greater than the cancellation judgment threshold value, the routine proceeds to step S 4 .
  • the wheel speed difference ⁇ vfr is judged to be equal to or less than the cancellation judgment threshold value, and the routine proceeds to step S 5 . This is to prevent a situation in which the bad road-detected control cannot be cancelled in the abnormal condition of the wheel speed sensor 21 . And, continuation of the bad road-detected control causes poor fuel economy.
  • a cancellation judgment timer is reset, and the routine is returned to step S 2 , then the bad road-detected control is continued.
  • the cancellation judgment timer is a timer that counts up when the wheel speed difference ⁇ vfr becomes equal to or less than the cancellation judgment threshold value.
  • step S 5 a judgment is made as to whether or not the vehicle speed vibration fvsp is equal to or less than a predetermined vibration value (corresponding to seventh and ninth predetermined values). If the condition is satisfied, the routine proceeds to step S 6 . If the condition is not satisfied, the routine is returned to step S 4 , and the cancellation judgment timer is reset.
  • a predetermined vibration value corresponding to seventh and ninth predetermined values
  • the bad road judgment is performed using the wheel speed difference. Because of this, if a judgment to end the bad road-detected control is made only using the wheel speed difference, there is a risk that the bad road-detected control will be ended due to a temporary convergence of the wheel speed difference even when the road is actually the bad road. In this case, even if the bad road judgment is immediately performed again, a problem about a response of the pressure control for increasing the compression force (the belt clamping force) arises, and there is a risk that the compression force cannot be increased before an occurrence of the belt slip.
  • the end judgment of the bad road-detected control is made by the vehicle speed vibration fvsp that is the vibration component of the vehicle speed, in addition to the wheel speed difference ⁇ vfr, thereby preventing a situation in which the bad road-detected control is accidentally ended.
  • the vibration component is detected on the basis of the sensor pulse period detected by the primary pulley rotation sensor 13 . Even if the transmission ratio is changed at this time, since frequency of its change is extremely low, an influence can be removed by the low-pass filter. And, in a case where a judgment is made as to whether or not vibration of the primary pulley 2 is equal to or less than a predetermined vibration value and the vibration is equal to or less than the predetermined vibration value, the routine proceeds to step S 6 . If the vibration is greater than the predetermined vibration value, the routine is returned to step S 4 , and the cancellation judgment timer is reset.
  • the compression force is increased by the bad road-detected control. In this case, the compression force cannot be returned to a low compression force of a normal state, then this causes poor fuel economy.
  • the abnormal condition of the wheel speed sensor 21 since the wheel speed difference is not used for the cancellation judgment, but only the vibration component of the primary pulley rotation sensor 13 is used for the cancellation judgment, it is possible to return the compression force to the low compression force of the normal state when the road condition becomes the good road, thereby suppressing poor fuel economy.
  • step S 6 the cancellation judgment timer counts up.
  • step S 7 a judgment is made as to whether or not a count value of the cancellation judgment timer is equal to or greater than a predetermined timer value. If the count value of the cancellation judgment timer is equal to or greater than the predetermined timer value, the routine proceeds to step S 8 . If the count value is less than the predetermined timer value, the routine is returned to step S 2 , and the bad road-detected control is continued.
  • step S 8 the bad road detection flag is set to OFF, and the bad road-detected control is cancelled.
  • this primary pulley minimum rotation speed Npri_min is also canceled.
  • FIG. 5 is a time chart showing the bad road control process according to the embodiment 1.
  • the vehicle travels at a substantially constant speed, the bad road detection flag is OFF, and the cancellation judgment timer counts up to a certain timer value.
  • the cancellation judgment timer is reset. Then, due to increase of the wheel speed difference ⁇ vfr, since the wheel speed difference ⁇ vfr exceeds ⁇ vfr_psec, the secondary pulley pressure Psec is gradually increased by the ramp control. Further, when the wheel speed difference ⁇ vfr exceeds ⁇ vfr_npri, the minimum rotation limit regulation is performed.
  • the bad road detection flag is set to ON from OFF, and the bad road-detected control is executed. With this, the wheel speed difference goes toward a convergence direction. Since the bad road detection is carried out on the basis of the wheel speed difference in this way, a rapid or quick bad road detection becomes possible, then the belt slip can be suppressed.
  • the bad road detection flag is set to OFF from ON, and the bad road-detected control is ended. Further, the secondary pulley pressure Psec also starts to decrease toward the normal control secondary pulley pressure Psec(n) at the predetermined change rate ⁇ Psec_lim, and the minimum rotation limit regulation process is also cancelled. In this way, at the cancellation of the bad road-detected control, by not only judging the wheel speed difference, but also judging the decrease of the vibration component, a stable cancellation judgment can be achieved.
  • the embodiment 1 can obtain the following effects.
  • a control device for a continuously variable transmission comprises: a wheel speed sensor 21 F (a first rotation speed sensor) detecting a rotation speed of a driving wheel; a wheel speed sensor 21 R (a second rotation speed sensor) detecting a rotation speed of a driven wheel; step S 04 (a wheel speed difference detection unit) configured to detect a wheel speed difference between the driving wheel and the driven wheel from a detection value of the wheel speed sensor 21 F and a detection value of the wheel speed sensor 21 R; step S 09 (a bad road judgment unit) configured to, when the wheel speed difference is equal to or greater than an entry judgment threshold value ⁇ vfr_br (a first predetermined value), judge that a road on which a vehicle is travelling is a bad road; step S 2 (a first belt clamping force increase unit) configured to, in a case where the road is judged to be the bad road, increase a belt clamping force when clamping a belt of the continuously variable transmission by pressure-controlled pulleys as compared with a case where the road is not judged to be the bad road
  • the compression force (the belt clamping force) can be immediately increased when the driving wheel slips. Therefore, the belt slip caused by increase of the grip force of the driving wheel after the slip can be avoided.
  • the CVT 1 (the continuously variable transmission) is a transmission in which the pulleys are pressure-controlled according to a discharge pressure of a mechanical oil pump O/P that is driven by an engine 5 , and the control device has step S 07 (a minimum rotation limit regulation unit) configured to, in the case where the road is not judged to be the bad road, when the wheel speed difference ⁇ vfr is equal to or greater than ⁇ vfr_npri (a fourth predetermined value) that is smaller than the entry judgment threshold value ⁇ vfr_br at step S 06 , or when the vehicle speed vibration fvsp is equal to or greater than fvsp_npri (a fifth predetermined value) at step S 06 , limit a rotation speed of the engine 5 so as to be Npri_min (a predetermined minimum rotation speed) or more.
  • Npri_min a predetermined minimum rotation speed
  • the lock-up clutch 6 c of the torque converter 6 is in a lock-up state, and the rotation speed Npri of the primary pulley 2 of the CVT 1 and an engine rotation speed Ne are identical. Since the mechanical oil pump O/P is driven by the engine 5 , if the engine rotation speed Ne is decreased when increasing the secondary pulley pressure Psec according to fvsp or ⁇ vfr, there is a risk that an adequate oil pump discharge pressure will not be secured. Therefore, in order to secure the oil pump discharge pressure of the mechanical oil pump O/P, the primary pulley minimum rotation speed Npri_min is set, and the minimum rotation limit regulation process to control the transmission ratio G of the CVT 1 to achieve this rotation speed is performed. With this control, the primary rotation speed Npri is secured, which results in the engine rotation speed Ne being secured, then the oil pump discharge pressure of the mechanical oil pump O/P is secured, and the belt slip is prevented.
  • Npri_min is a predetermined constant value. Therefore, even if the minimum rotation limit regulation is carried out, the engine rotation speed is not changed, then an awkward or odd feeling which a driver is subjected to can be suppressed.
  • Step S 07 the minimum rotation limit regulation unit is configured to, when the regulation is started and the road is judged to be the bad road, continues the regulation until the wheel speed difference ⁇ vfr is equal to or less than a cancellation judgment threshold value (a sixth predetermined value) that is smaller than vfr_npri and the vehicle speed vibration fvsp is equal to or less than a predetermined vibration value (a seventh predetermined value) that is smaller than fvsp_npri.
  • the discharge pressure of the mechanical oil pump O/P can be adequately secured during execution of the bad road control process.
  • the control device has step S 8 (an increase cancellation unit) configured to, when the wheel speed difference ⁇ vfr is equal to or less than a cancellation judgment threshold value (an eighth predetermined value) that is smaller than the entry judgment threshold value ⁇ vfr_br and the vehicle speed vibration fvsp is equal to or less than a predetermined vibration value (a ninth predetermined value) that is smaller than fvsp_psec during increase of the belt clamping force by the bad road control process (the first belt clamping force increase unit), decrease the belt clamping force increased at step S 2 .
  • a cancellation judgment threshold value an eighth predetermined value
  • a predetermined vibration value a ninth predetermined value
  • the increased compression force is decreased when the wheel speed difference ⁇ vfr and the vehicle speed vibration fvsp become the respective predetermined values or less, it is possible to accurately judge that the vehicle gets out of the bad road. Further, it is possible to prevent the compression force from being decreased even in a case where the vehicle travels on such a road that the input torque is abruptly increased, then the belt slip can be avoided. Moreover, since the compression force is decreased to a compression force according to the good road when the wheel speed difference and the vehicle speed vibration converge, a time when the vehicle travels with the compression force being superfluously high even when returning to the good road can be shortened, thereby suppressing poor fuel economy.
  • the predetermined primary pulley minimum rotation speed Npri_min when performing the minimum rotation limit regulation at step S 07 , the predetermined primary pulley minimum rotation speed Npri_min is set.
  • a minimum rotation speed Npri_min is set on the basis of the secondary pulley pressure Psec(fvsp, ⁇ vfr) according to the vehicle speed vibration fvsp and/or the wheel speed difference ⁇ vfr. More specifically, when the wheel speed difference ⁇ vfr is less than ⁇ vfr_psec, the secondary pulley pressure Psec is the secondary pulley pressure Psec(fvsp) according to the vehicle speed vibration fvsp.
  • the secondary pulley pressure Psec is the secondary pulley pressure Psec(fvsp, ⁇ vfr) determined by the ramp control of step S 05 .
  • a minimum rotation speed Npri_min(fvsp, ⁇ vfr) required to secure this hydraulic pressure can be calculated from a specific discharge amount of the mechanical oil pump O/P.
  • Npri_min(fvsp, ⁇ vfr) (the predetermined minimum rotation speed) is set so that the greater the wheel speed difference ⁇ vfr is, the higher the Npri_min(fvsp, ⁇ vfr) is, or so that the greater the detected vehicle speed vibration fvsp is, the higher the Npri_min(fvsp, ⁇ vfr) is.
  • the predetermined vibration value (the seventh predetermined value) and the cancellation judgment threshold value (the eighth predetermined value) which are the cancellation conditions of the bad road control process are respectively set to the same values as the predetermined vibration value (the seventh predetermined value) and the cancellation judgment threshold value (the sixth predetermined value) which are the cancellation conditions of the minimum rotation limit regulation.
  • different values between the cancellation condition of the bad road control process and the cancellation condition of the minimum rotation limit regulation could be set.
  • the value of the cancellation condition of the minimum rotation limit regulation could be set to be higher than that of the cancellation condition of the bad road control process, and the minimum rotation limit regulation is early cancelled.
  • the embodiment 1 shows an example in which the present invention is applied to a front-wheel-drive vehicle.
  • the present invention can be applied to a four-wheel drive vehicle.
  • all wheels are driving wheels, there is a possibility that an adequate wheel speed difference will not be generated.
  • the bad road judgment at step S 9 the following two conditions are provided.
  • the road is judged to be the bad road.
  • the bad road detection can be effectively performed.
  • the bad road-detected control is cancelled by the conditions of the wheel speed difference and the vehicle speed vibration. With this, it is possible to immediately decrease the compression force (the belt clamping force) when returning to the good road or when mistakenly judged to be the bad road, thereby suppressing poor fuel economy.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Control Of Transmission Device (AREA)
  • Control Of Driving Devices And Active Controlling Of Vehicle (AREA)
US15/559,472 2015-03-20 2016-02-03 Control device for continuously variable transmission Active 2036-04-13 US10316967B2 (en)

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JP2015057518 2015-03-20
JP2015-057518 2015-03-20
PCT/JP2016/053167 WO2016152260A1 (fr) 2015-03-20 2016-02-03 Dispositif de commande pour transmission à variation continue

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KR102532321B1 (ko) * 2018-03-23 2023-05-15 현대자동차주식회사 무단변속기 차량의 풀리 제어방법
US10641391B2 (en) * 2018-04-23 2020-05-05 GM Global Technology Operations LLC System and method for CVT clamp control based on oncoming conditions in a vehicle propulsion system
CN111963671B (zh) * 2020-08-18 2021-12-31 盛瑞传动股份有限公司 自动变速箱颠簸路面控制方法及控制装置
CN112797156B (zh) * 2021-02-07 2022-04-26 潍柴动力股份有限公司 一种换挡控制方法、装置及控制器
CN113464638B (zh) * 2021-06-30 2022-06-28 中国第一汽车股份有限公司 一种手动模式换挡控制方法和车辆

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WO2016152260A1 (fr) 2016-09-29
CN107429837A (zh) 2017-12-01
JPWO2016152260A1 (ja) 2017-10-19
US20180119813A1 (en) 2018-05-03
JP6340135B2 (ja) 2018-06-06
KR102004635B1 (ko) 2019-07-26
EP3273111A1 (fr) 2018-01-24
EP3273111A4 (fr) 2018-05-02
CN107429837B (zh) 2019-05-21

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